Method and device for producing wave windings for a stator of a three-phase generator

ABSTRACT

A method and device for producing wave windings for an electrical machine, especially for a three-phase generator, is described in which each phase has a wave winding ( 12 ) divided into two winding halves ( 12   a   ,12   b ), which are first deformed into a wavy star shape, are offset from one another by one pole pitch, and are finally inserted jointly into the grooves of a stator lamination packet. A simple and reliable method for production of this wave winding includes first winding a first winding half ( 12   a ) in a first winding direction in a circular or polygonal shape, and then switching over the continuous winding wire ( 15 ) in a winding loop ( 21 ) into the opposite winding direction, then winding the second winding half ( 12   b ) in the opposite winding direction and deforming both winding halves simultaneously into a star shape, offsetting both winding halves ( 12   a   , 12   b ) with respect to each other by one pole pitch (p) so that the winding loop ( 21 ) between the winding halves transitions into the star shape.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and device for producing wavewindings for electrical machines, especially for a stator of athree-phase generator.

2. Prior Art

The invention is based on a method and a device for producing wavewindings for electric machines according to U.S. Pat. No. 4,857,787. Inthat instance, the winding for each phase of a three-phase generator isfirst wound onto a drum or a polygon with the necessary number ofwindings and is then deformed into a star shape. After this, the windingis folded into two halves so that the two halves are disposed next toone another. Then the two halves are pivoted in such a way that the gapsof the star-shaped loops or waves of one winding half have a loop of theother winding half disposed in them. The wave winding of the one phasethat is prepared in this manner is then inserted axially in a knownmanner into the slots of a stator lamination packet. In the same manner,the winding of the second and third phase of the three-phase generatorare then successively preformed, divided, pivoted in relation to eachother so that they are offset from one another, and inserted into thestator lamination packet.

The division of each phase winding into two parts and the pivoting inrelation to one another is relatively costly in this method and can beproduced by means of commercially available robots for a large-scalemass production only with a multitude of malfunction-prone manufacturingsteps.

The automatic large-scale mass production of two-part wave windings withwaves of that are offset from one another should be simplified andimproved with the current embodiment.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved methodfor producing wave windings for electrical machines, especially for astator of a three-phase generator, which is simpler than the currentmethod.

It is another object of the present invention to provide an improveddevice for producing wave windings for electrical machines, especiallyfor a stator of a three-phase generator.

According to the invention the method provides a wave winding for astator of a three-phase generator, which is divided into two windinghalves, each consisting of at least one continuous winding wire. Eachwinding half is in a circular or polygonal shape or deformed into a starshape. They are offset from each other by one pole pitch (p). The wavewinding is arranged in grooves provided in a stator lamination packet sothat alternating winding heads of the two winding halves are formed onboth sides of the stator lamination packet around a circumference of thestator lamination packet. The method comprises the steps of:

a) winding the at least one continuous winding wire in a first windingdirection to form a first winding half in the circular or polygonalshape;

b) switching over the at least one continuous winding wire into anopposite winding direction in a winding loop;

c) after the switching over of the at least one continuous winding wire,winding the at least one continuous winding wire in the opposite windingdirection to form a second winding half in the circular or polygonalshape;

d) simultaneously deforming both the first winding half and the secondwinding half into a star shape; and

e) after the deforming of step d) rotating the first winding half andthe second winding half with respect to each other by one pole pitch, sothat the winding loop between the first winding half and second windinghalf transitions into the star shape.

The device according to the invention comprises means for winding the atleast one continuous winding wire in a first winding direction to form afirst winding half in the circular or polygonal shape; means forswitching over the at least one continuous winding wire into an oppositewinding direction in a winding loop after the formation of the firstwinding half; means for winding the at least one continuous winding wirein the opposite winding direction to form a second winding half in thecircular or polygonal shape after the switching over; means forsimultaneously deforming both first winding half and the second windinghalf into a star shape and means for rotating the first winding half andsecond winding half with respect to each other by one pole pitch afterthe deforming so that the winding loop between the first winding halfand second winding half transitions into the star shape.

The means for winding the at least one continuous winding wire to formthe first winding half and the second winding half in the deviceaccording to the invention comprises a winding bell rotatable in eitherof two rotation directions, a plurality of radially movable formingclamps connected to the winding bell and arranged around itscircumference, so that the at least one continuous winding wire is woundaround the forming clamps.

The means for switching over comprises a loop puller for forming thewinding loop and the means for deforming both first winding half andsecond winding half comprises forming levers and means for moving theforming levers radially inward to engage with the first winding half andthe second winding half wound around the forming clamps.

The method according to the invention and the provided device forproducing wave winding halves that are offset from one another,according to the characterizing features of the invention has theadvantage that on a winding bell, the two continuous winding halves thatare wound one after the other are already wound in an opposite windingdirection to one another and deformed into a star shape. By way of awinding loop that is formed between the two winding halves, the twowinding halves can then be rotated to the left or right in relation toeach other by one pole pitch so that the waves of the two windinghalves, which are embodied as star-shaped, are then offset in relationto each other by one pole pitch. Subsequently, the wave winding that ispreformed in this fashion is inserted in a known manner into a statorlamination packet of a generator. In the same manner, all three-phasewindings of the three-phase generators are produced separately as wavewindings and are inserted one after the other into the stator laminationpacket. In this manner, the wave windings, with winding halves that areoffset from one another, can be produced in a simple and reliable mannerin a few work steps in one winding station, and can be transferred to aninsertion station.

BRIEF DESCRIPTION OF THE DRAWING

The objects, features and advantages of the invention will now beillustrated in more detail with the aid of the following description ofthe preferred embodiments, with reference to the accompanying figures inwhich:

FIGS. 1(a) and 1(b) are, respectively, schematic action plan viewsshowing the winding of a first coil half;

FIGS. 2(a) and 2(b) are, respectively, schematic action plan viewsshowing the winding of a loop with reversal of winding direction;

FIGS. 3(a), 3(b) and 3(c) are, respectively, schematic action plan viewsshowing the winding of a second winding half;

FIG. 4 is a perspective view of a winding device with an insertion toolunder it;

FIG. 5 is a diagrammatic plan view of a star-shaped, previously formedwinding;

FIG. 6 is a diagrammatic cutaway perspective view of a wave winding,whose one half has been stripped into the insertion tool;

FIG. 7 is a diagrammatic cutaway perspective similar to FIG. 6, showingrotation of the upper winding half;

FIG. 8 is a plan view of a finished wave winding arranged in theinsertion tool;

FIG. 9 is a cutaway longitudinal cross-sectional view showing the wavewinding and the insertion tool after insertion of the wave winding;

FIG. 10 is a perspective view of a stator lamination packet with onedivided wave winding shown; and

FIG. 11 is a perspective view of the finished stator with three phasewindings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to produce a stator 10 according to FIG. 11, with a three-phasewave winding 11, each of the three-phase strands is produced in advanceon a winding device 13 according to FIG. 4 by means of a wave winding 12with winding halves 12 a and 12 b that are offset from one another.FIGS. 1 to 3 schematically depict the production of such a wave winding12 from FIG. 10. A wire clamp 14 secures one end 15 a of a winding wire15 according to FIG. 1b at the lower end of a forming clamp 16.According to FIG. 1a, six of these forming clamps are arranged in a starshape in the winding device 13. The winding wire 15 is withdrawn from astorage drum, not shown, by way of a wire orifice 17. The forming clamps16 are disposed so that they can move radially in a winding bell 18 ofthe winding device 13 according to FIG. 4. In order to produce the firstwinding half 12 a, the forming clamps 16 are rotated clockwise with thewinding bell 18 so that the first winding half 12 a is produced withfour complete windings in a polygonal form.

Now the winding device is stopped, wherein the forming clamp 16 a staysat the level of the wire orifice 17. It is clear from FIG. 2 that in itsfront region, the forming clamp 16 a has a segment-shaped recess 19, inthe front of which an axially extending, strut-shaped loop puller 20remains. The wire orifice 17 is now conveyed to this loop puller and thewinding wire 15 from the wire orifice 17 is now conveyed up from thebottom around the loop puller 20, wherein the forming clamps 16 and 16 aare moved axially downward together with the winding bell 18.

Now the winding bell 18 is slowly rotated further counter-clockwise andthe wire orifice 17 is moved back into its outer position. This producesa winding loop 21 on the loop puller 20 as can be seen in FIG. 2b.

According to FIG. 3, the second winding half 12 b is now produced in theopposite winding direction by means of a corresponding number ofrotations of the winding bell 18.

FIG. 4 is a three-dimensional depiction of the winding device 13 forproducing the wave winding 12. It is clear from this figure that on theunderside of the winding bell 18, the six forming clamps 16 are disposedin a polygonal arrangement so that they can be moved on inwardlyextending on axles 22, wherein the drive 16 b is supplied pneumatically,via Bowden cables, or via other means. Forming levers 23 arerespectively disposed between the forming clamps 16 and can likewise berespectively moved by way of a drive mechanism 23 a on radially disposedaxles 24 by pneumatic means, a Bowden cable, or the like. The sixforming levers 23 are depicted in FIG. 4 in their outer position,pivoted up and in so that during the winding of the first and secondwinding halves 12 a and 12 b, they cannot protruding into the windingregion. On the back side of the forming clamps 16, a stripper 25 isdisposed so that it can be moved axially, which stripper protrudes abovethe first winding half 12 a with a stripper arm 25 a and protrudes abovethe second winding half 12 b with another stripper arm 25 b, as can beseen in FIGS. 1b to 3 b. The winding bell 18 can be rotated by a drivemechanism 26 in the direction of the arrows in both rotation directions,and can also be moved in the axial direction.

Beneath the winding bell 18 an insertion tool 27 is disposed, which hasa receiving crown 28 and insertion needles 29 disposed radially insidethem (visible in FIG. 8). The receiving crown 28 is provided withlongitudinal slots 30 between the insertion needles 29. The insertiontool 27 rests on a tool table 31 that can be pivoted and can likewise beadjusted with regard to its height.

In another process step, the upper and lower winding halves 12 a and 12b are now simultaneously deformed into a star shape according to FIG. 5,in which the six forming clamps 23 are first folded outward in aperpendicular fashion by their drive mechanism 23 a and are then movedradially inward via the axles 24, as indicated by the arrows in FIG. 5.Simultaneous to this, the forming clamps 16 are slid radially inward ina yielding fashion on their axles 22, which is likewise indicated inFIG. 5 by means of corresponding arrows. Both winding halves 12 a and 12b are now disposed in a star shape spaced one above the other on theforming clamps 16 and the forming levers 23.

In other steps, the forming clamps 16 are then moved by 3 mm in thearrow direction according to FIG. 5, the coil 12 is released, the wireclamp 14 is opened, and then the lower winding half 12 a is strippedfrom the forming clamps 16 by the strippers 25 according to FIG. 6,wherein these winding halves are received with their star-shaped legsinto longitudinal slots 30 of the receiving crown 18 of the insertiontool 27. The upper winding half 12 b is likewise slid downward by thestrippers 25 b, but remains in the lower region of the forming clamps.The upper and lower winding halves 12 a and 12 b are now connected toone another only by way of the winding loop 21.

In the subsequent process step, the winding bell 18 is then rotated backto the left by one pole pitch p of the twelve-polled wave winding 12,i.e. by 30 ° in the direction of the arrow, so that the star-shapedwaves of the two winding halves 12 a and 12 b are now offset in relationto one another. The winding loop 21 is moved to the left so that itlikewise follows the course of the upper winding half 12 b.

In another process step, the upper winding half 12 b is also strippedfrom the forming clamps 16 by the stripper 25 and is inserted into thelongitudinal slots 30 of the receiving crown 28 of the insertion tool.As shown by FIG. 8, the waves of the two winding halves 12 a and 12 bare now disposed symmetrically offset from one another in thelongitudinal slots 30 of the receiving crown 28. In this state, thestrippers 25 are lifted up again. The forming levers are now returnedback into the outer position and thereby pivoted back into their initialposition according to FIG. 4, and the winding bell 18 moves upward. Astator lamination packets 32 is fixed to the upper part 28 a (FIG. 4) ofthe receiving crown 28. Then the tool table 31 pivots in relation to aninsertion station 34 that is schematically depicted in FIG. 9. Thepreformed wave winding 12 is inserted in a known manner into the groovesof the stator lamination packet 32 by means of an insertion die 33, andthe upper winding heads 12 c are pressed radially outward into theposition shown in FIG. 10 by means of press-back clamps 35. A grooveclosure is also carried out in this station. In this manner, alternatingwinding heads 12 c are formed from the two winding halves on both sidesover the circumference of the stator lamination packet 32. In thisconnection, the stator lamination packet 32 is secured on the receivingcrown 28 by a packet clamping ring 36.

In the manner described above, another wave winding is now produced onthe winding device according to FIG. 4 and is deformed into a starshape. Then the two winding halves are rotated in relation to each otherby one pole pitch in the above-described manner, are then taken by theinsertion tool and finally inserted into the stator lamination packetnext to the first wave winding, in the grooves provided for thispurpose. The production and insertion of the third wave winding alsooccurs in the same manner so that in the end, a finished statoraccording to FIG. 11 is produced, which has a three-phase wave winding11. The beginnings and ends of the three phases of the three-phase wavewinding are labeled there with the letters U, V, W and X, Y, Z.

With these wave windings which are respectively offset from one anotherin opposite directions, the groove-filling factor in the statorlamination packet 32 can be increased by up to 10% in comparison to aone-piece wave windings. In generators with higher outputs, thegroove-filling factor can also be increased further by virtue of thefact that instead of one winding wire with a relatively largecross-section, two or more winding wires with correspondingly smallercross sections can be wound and connected parallel to one another.

The pivoting of the two winding halves 12 a and 12 b in relation to eachother in the winding device according to FIG. 4 can also occur in thesame manner by means of rotating the upper winding half 12 b toward theright in relation to the lower winding half 12 a. In this instance, thewinding loop 21 would not be folded toward the upper winding half 12 bin accordance with FIG. 7, but would be folded toward the lower windinghalf 12 a. In this instance, the winding beginning of the lower windinghalf 12 a and the winding end of the upper winding half 12 b have to becorrespondingly positioned so that the lower winding half 12 a does notbecome longer and so that the upper winding half 12 b does not becomeshorter. In the same manner, the two winding halves 12 a and 12 b canalternatively also be wound in the opposite winding direction onto theforming clamps—i.e. the first half toward the right and the second halftoward the left. In this instance, the loop puller must be disposed onthe right side on the forming clamp 16 a. With a disposition of the looppuller 21 in the center of the forming clamp 16 a, the winding devicecan be used for both winding directions.

In any case, the current flow in the winding sections of the two windinghalves inside the grooves of the lamination packet always remains thesame through the rotation by 30°, i.e. by one pole pitch.

Since the wave winding is also divided into two halves in bothdirections at the groove outlet, the three winding strands on the coilheads only ever intersect with half the number of line wires of aneighboring phase winding. In comparison to an undivided winding, thisresults in a flatter winding head with a more uniform wire routing,along with a current noise reduction and improved cooling.

What is claimed is:
 1. A method of making a wave winding for a stator of a three-phase generator, wherein said wave winding (12) is divided into two winding halves (12 a, 12 b), each of said two winding halves consists of at least one continuous winding wire (15) wound in a circular or polygonal shape or deformed into a star shape, said two winding halves are offset from each other by one pole pitch (p) and arranged in grooves provided in a stator lamination packet (32) so that alternating winding heads (12 c) of the two winding halves are formed on both sides of said stator lamination packet around a circumference of said stator lamination packet, said method comprising the steps of: a) winding said at least one continuous winding wire in a first winding direction to form a first winding half (12 a) in said circular or polygonal shape; b) switching over said at least one continuous winding wire into an opposite winding direction in a winding loop (21); c) after the switching over of said at least one continuous winding wire, winding said at least one continuous winding wire in the opposite winding direction to form a second winding half (12 b) in said circular or polygonal shape; d) simultaneously deforming both said first winding half (12 a) and said second winding half (12 b) into said star shape; e) after said deforming of step d), rotating said first winding half (12 a) and said second winding half (12 b) with respect to each other by said one pole pitch (p), whereby said winding loop (21) between said first winding half (12 a) and said second winding half (12 b) transitions into said star shape.
 2. The method as defined in claim 1, further comprising providing a winding bell (18) rotatable in either of two rotation directions, a plurality of radially movable forming clamps (16) connected to the winding bell and arranged around a circumference of said winding bell (18), a loop puller (20) for deforming said at least one continuous winding wire, forming levers (23) for deforming said first winding half (12 a) and said second winding half (12 b) into said star shape and a receiving device for removing the first winding half (12 a) and the second winding half (12 b) from the forming clamps (16); and wherein the first winding half (12 a) is wound onto the forming clamps (16), then said winding loop (21) for the opposite winding direction is formed by engaging said at least one continuous winding wire with said loop puller (20), subsequently said second winding half (12 b) is wound onto said forming clamps (16) in the opposite winding direction so as to be axially offset with respect to said first winding half (12 a), after the first winding half (12 a) and the second winding half (12 b) are wound on the forming clamps (16), deforming simultaneously said first winding half (12 a) and said second winding half (12 b) into a wavy star configuration by moving said forming levers (23) uniformly radially inward; then removing said first winding half (12 a) from the forming clamps (16) by means of the receiving device; subsequently rotating the second winding half (12 b) by said one pole pitch (p) and finally removing said second winding half (12 b) from the forming clamps (16) of the winding bell (18) with the receiving device.
 3. The method as defined in claim 2, wherein said receiving device comprises an insertion tool (27) and said loop puller (20) is arranged on a first one (16 a) of said forming clamps (16).
 4. A device for making a wave winding for a stator of a three-phase generator, wherein said wave winding (12) is divided into two winding halves (12 a, 12 b), each of said two winding halves consists of at least one continuous winding wire (15) in a circular or polygonal shape or deformed into a star shape, said two winding halves are offset from each other by one pole pitch (p) and arranged in grooves provided in a stator lamination packet (32), so that alternating winding heads (12 c) of the two winding halves are formed on both sides of said stator lamination packet around a circumference of said stator lamination packet, said device comprising: means for winding said at least one continuous winding wire in a first winding direction to form a first winding half (12 a) in said circular or polygonal shape; means for switching over said at least one continuous winding wire into an opposite winding direction in a winding loop (21) after the formation of the first winding half (12 a); means for winding said at least one continuous winding wire in the opposite winding direction to form a second winding half (12 b) in said circular or polygonal shape after the switching over; means for simultaneously deforming both said first winding half (12 a) and said second winding half (12 b) into said star shape; and means for rotating said first winding half (12 a) and said second winding half (12 b) with respect to each other by said one pole pitch (p) after the deforming, whereby said winding loop (21) between said first winding half (12 a) and said second winding half (12 b) transitions into said star shape; wherein said means for winding said at least one continuous winding wire to form said first winding half (12 a) and said second winding half (12 b) comprises a winding bell (18), said winding bell having a circumference and being rotatable in either of two rotation directions, a plurality of radially movable forming clamps (16) connected to the winding bell and arranged around said circumference of said winding bell (18), said at least one continuous winding wire being wound around said forming clamps (16); wherein said means for switching over comprises a loop puller (20) for forming said winding loop (21); and wherein said means for deforming both said first winding half (12 a) and said second winding half (12 b) comprises forming levers (23) and means (23 a) for moving said forming levers radially inward to engage with said first winding half (12 a) and said second winding half (12 b) wound around said forming clamps (16).
 5. The device as defined in claim 4, wherein said means for rotating said first winding half (12 a) and said second winding half (12 b) with respect to each other comprises strippers (25) arranged in the vicinity of said forming clamps (16) for said first winding half (12 a) and said second winding half (12 b) and means for axially moving said strippers (25) and for engaging said first winding half (12 a) and said second winding half (12 b) with said strippers (25) to remove one of said first winding half and said second winding half from said winding bell (18) in order to be able to rotate another of said first winding half and said second winding half with respect to said one of said first winding half and said second winding half whereby said winding loop (21) transitions into said star shape.
 6. The device as defined in claim 4, wherein said loop puller (20) comprises an axial strut arranged in a segment-shaped recess (19) on a front end of one (16 a) of said forming clamps (16). 